Four new hybrid architectures containing a [Co2Mo10H4O38]6– polyoxoanion, (en)[Cu3(ptz)4(H2O)4][Co2Mo10H4O38]·24H2O (1), (Hbim)2[{Cu(bim)2(H2O)2}2{Co2Mo10H4O38}]·5H2O (2), H2[Cu(dpdo)3(H2O)4][{Cu2(dpdo)3(H2O)4(CH3CN)}2{Co2Mo10H4O38}2]·9H2O (3), and (H2bpp)4[{Cu(H2O)2}{NaCo2Mo10H4O38}2]·10H2O (4), where ptz = 5-(4-pyridyl)-1H-tetrazole, en = ethylenediamine, bim = benzimidazole, dpdo = 4,4′-bipyridine-N,N′-dioxide, and bpp = 1,3-bis(4-pyridyl)propane, have been prepared and characterized through elemental analysis, thermogravimetric analysis, IR spectroscopy, and powder and single-crystal X-ray diffraction. Compound 1 shows a 3D host–guest framework composed of 3D Cu-ptz as the host and Evans–Showell-type polyoxoanion [Co2Mo10H4O38]6– as the guest. Compound 2 is constructed from [Co2Mo10H4O38]6– polyoxoanions and Cu-bim coordination complexes to form a 2D covalent layer. Compound 3 also exhibits a 2D hybrid network based on [Co2Mo10H4O38]6– polyoxoanions linked by Cu-dpdo coordination groups. Compound 4 is a 1D double-chain structure composed of [Co2Mo10H4O38]6– polyoxoanions joined together by Na+ and Cu2+ cations. As far as we know, compound 1 is the first host–guest compound with an Evans–Showell-type polyoxometalate as the guest, and compounds 2 and 3 are the first 2D inorganic–organic hybrid architectures constructed from Evans–Showell-type polyoxometalates. Compounds 1–4 are redox catalysts that heterogeneously prompt sulfide and alcohol oxidation with excellent efficiency.

Four new architectures containing [Co2Mo10H4O38]6− polyoxoanions, (C2N2H10)2[Sr(H2O)5][Co2Mo10H4O38]·2H2O 1, (C2N2H10)2[Ba(H2O)3][Co2Mo10H4O38]·3H2O 2, (C3N2H12)2[Sr(H2O)5][Co2Mo10H4O38]·3H2O 3 and (C3N2H12)[Ba(H2O)4][Ba(H2O)4][Co2Mo10H4O38]·2H2O 4 (C2N2H10 = ethylenediamine; C3N2H12 = 1,3-propanediamine) have been synthesized and characterized by elemental analysis, IR spectroscopy, solid diffuse reflective spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 obtained in the presence of ethylenediamine, are made of Evans–Showell-type anions [Co2Mo10H4O38]6−, linked by Sr2+ or Ba2+ cations to form 3D frameworks. To our knowledge, compound 1(2) represents the first example of 3D architecture in which the Evans–Showell anions [Co2Mo10H4O38]6− were linked by pure alkaline earth cations. When propanediamine was used instead of ethylenediamine, compounds 3 and 4 with 2D networks were obtained. This phenomenon indicates that the organic cations, which adjust the reaction pH values, can induce different dimensional inorganic frameworks. As heterogeneous catalysts, compounds 1–4 show excellent catalytic performance in the cyanosilylation of carbonyl compounds. Furthermore, these catalytic reactions were performed under solvent-free conditions using only a low amount of the catalysts, and these catalysts can be recovered and reused without displaying any significant loss of activity. As far as we know, compounds 1–4 represent the first examples of cyanosilylation catalyzed by POM-based species containing alkaline earth metal cations.

Six new hybrid compounds based on [Co2Mo10H4O38]6– polyoxoanion, (4-H2pya)6Co2Mo10H4O38·10H2O 1 (4-Hpya =3-(4-pyridyl)acrylic acid) and (4-H2pya)4[M(H2O)6][Co2Mo10H4O38]·5H2O (M = Co 2, Ni 3, Cu 4, Zn 5, Cd 6), were synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, solid diffuse reflective spectrum, powder X-ray diffraction, and single crystal X-ray diffraction. Compound 1 crystallizes in the centrosymmetric space group P-1, which is built up of protonated 4-H2pya molecules and isolated [Co2Mo10H4O38]6– polyoxoanions. Isostructural compounds 2–6 crystallize in the chiral space group P1 by spontaneous resolution, as a conglomerate of two enantiomerically pure crystals, which were obtained by adding different metal cations to the reaction system of compound 1. The structures of 2–6 comprise chiral [Co2Mo10H4O38]6– anions, cationic [M(H2O)6]2+ units, and protonated 4-H2pya ligands. The chiral [Co2Mo10H4O38]6– polyoxoanions can be connected up together by directional hydrogen-bonding interactions among terminal oxygen atoms of anions, coordinated water molecules and organic ligands to construct a 3D supramolecular chiral framework in 2–6. The absolute configuration of 2–6 was determined from the Flack parameter by X-ray crystallography and solid state circular dichroism spectroscopy. As far as we know, compounds 2–6 represent the first examples of chiral inroganic-organic hybrid species based on Evans–Showell-type polyoxometalates. Furthermore, the second harmonic generation (SHG) activities for 2 and 4 were measured, showing an SHG efficiency of approximately 0.9 × KH2PO4.

By controlling the reaction temperatures, four new architectures based on Evans–Showell type polyoxometalate, [Ln(H2O)5][Ln(H2O)7][Co2Mo10H4O38] 6H2O (Ln = Sm 1; Eu 2), and (NH4)3[Ln(H2O)6][Co2Mo10H4O38] 6H2O (Ln = Sm 3; Eu 4) have been synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, solid diffuse reflective spectrum, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 are racemic compounds, obtained at the higher temperature (85 °C). They show a 1D ladderlike structure constructed from left-handed chain and right-handed chain linked by lanthanide cations, which represent the first 1D self assembly based on Evans–Showell type polyoxometalate. When the reaction temperature was decreased to room temperature (25 °C), two chiral species 3 and 4 were obtained, showing a mono-supporting structure composed of one [Co2Mo10H4O38]6− polyoxoanion and one [Ln(H2O)6]3+ unit. They crystallize in the chiral space group P21, as conglomerates of two enantiomerically pure crystals. Their absolute configuration were determined by the Flack parameters and solid state circular dichroism spectroscopy. The structural differences between 1(2) and 3(4) reveal that the reaction temperature is the key factor controlling the products from racemic compounds to conglomerates. Four compounds 1–4 acted as Lewis acid–base catalysts through a heterogeneous manner to catalyse cyanosilylation with excellent efficiency.

Four new architectures containing [Co2Mo10H4O38]6– polyoxoanion, [Ln(H2O)7][Ln(H2O)5][Co2Mo10H4O38]·5H2O (Ln = Gd 1; Tb 2), and (NH4)3[Ln(H2O)6][Co2Mo10H4O38]·6H2O (Ln = Gd 3; Tb 4) have been synthesized at different temperatures and characterized by elemental analysis, IR and Raman spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Isostructural compounds 1 and 2 obtained at the higher temperature (85 °C), are built up of Evans–Showell-type polyoxoanions [Co2Mo10H4O38]6–, respectively, linked by Gd3+ or Tb3+ cations to form a 3D racemic framework with 1D zigzag channels. From the topological point of view, the 3D net is a rare binodal 4-connected SrAl2 (sra) topology. As far as we know, compounds 1 and 2 represent the first examples of 3D architectures based on Evans–Showell-type polyoxometalate. Interestingly, the stable 3D microporous compounds exhibit selective adsorption ability: adsorbing water and methanol, as well as excellent photocatalytic activity for organic dye degradation under visible light irradiation. When the reaction temperature was decreased to room temperature (25 °C), two chiral species 3 and 4 were obtained, with a monosupporting structure composed of one [Co2Mo10H4O38]6– polyoxoanion and one [Ln(H2O)6]3+ unit. These chiral monosupporting motifs can be connected by strong hydrogen-bonding interactions to form a 3D chiral supramolecular architecture. They crystallize in the chiral space group P21, as conglomerates of two enantiomerically pure crystals. Their absolute configurations were determined by the Flack parameters and solid-state circular dichroism spectroscopy.

Three new lanthanide-supported molybdovanadates [Ln(H2O)5]2Mo6V2O26·8H2O (Ln = La 1; Ce 2; Nd 3) have been synthesized by the reaction of the [Mo6V2O26]6− anion with Ln(NO3)3 in aqueous solution and characterized by elemental analysis, IR, solid state UV-vis spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Compounds 1–3 are obtained at the same pH value (3.0) and have similar structural units which consist of one molybdovanadate unit supported by two lanthanide cations. Then, these bi-supporting subunits are joined together by strong hydrogen-bonding interactions between polyoxoanions and coordinated water molecules to form a 3D supramolecular framework. To the best of our knowledge, they represent the first examples of inorganic species constructed from molybdenum–vanadium polyoxometalates and lanthanides. The UV-vis diffuse reflectivity spectra of 1–3 show that they can be regarded as a wide gap semiconductor. Photocatalytic studies indicate that compounds 1–3 are not only active photocatalysts for degradation of rhodamine B, but very stable and easily separated from the photocatalytic system for reuse as well. Moreover, the new materials were tested as catalysts in cyanosilylation reactions of aldehydes under solvent-free conditions. The experimental results indicate that all three compounds 1–3 can act as Lewis acid–base catalysts through a heterogeneous manner to prompt cyanosilylation with good efficiency.

Three new architectures based on Anderson-type polyoxometalates, (3-H2pya)[(3-Hpya)2Ag][AgAlMo6H6O24]·3H2O 1, HNa2[(3-pya)(3-Hpya)Ag]2[AlMo6H6O24]·8H2O 2 and [(3-Hpya)2Ag][(H2O)2Ag]2[AlMo6H6O24]·2H2O 3 (3-Hpya = 3-(3-pyridyl)acrylic acid), have been synthesized at the different pH values and characterized by elemental analysis, IR spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compound 1 was obtained at lower pH value (2.50), and represents a 3D host–guest compound containing the Ag-3-Hpya coordination complex guest and the 3D [AgAlMo6H6O24]2− host. The host framework exhibits a 4-connected diamond topology, and is constructed from [AlMo6H6O24]3− clusters connected by Ag+ cations. When the pH value was increased slightly, compound 2 was obtained with a 1D chain structure built up of Anderson polyoxoanions, Ag-3-Hpya coordination complexes and binuclear sodium clusters. By further increasing the pH value (3.50), compound 3 was isolated as a 2D network in which [AlMo6H6O24]3− clusters are linked together by Ag+ cations and Ag-3-Hpya coordination complexes. Their structural differences reveal that the pH value of the reaction system is the key factor influencing the structure and topology of three compounds. The UV-visible-NIR diffuse reflectivity spectra of 1–3 show that they can be regarded as a wide gap semiconductor. Furthermore, the pyrolysis of 1–3 produces three nanocomposites 1′–3′ composed of silver microparticles dispersed in the metal oxides. The photocatalytic properties of 1′–3′ have been investigated.

Six new hybrid species based on amino acid functionalized γ-octamolybdates, [(H2O)3M]2[Mo8O26(pro)2]·2H2O (M = Cu 1, Zn 2, Co 3), [(H2O)8(lys)2Cu3][Mo8O27]·12H2O (4), and [(H2O)6M][Mo8O26(lysH)2]·4H2O (M = Zn 5, Co 6) (pro = proline; lys, lysH = lysine), have been synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1–3 are isostructural, consisting of proline functionalized γ-octamolybdates linked by metal cations (M = Cu2+, Zn2+ and Co2+) to form a 2D framework with 4-connected topology. The proline functionalized γ-octamolybdates [Mo8O26(pro)2]4− consist of two γ-type [Mo8O26]4− anions covalently bridged by two proline molecules via the carboxyl oxygen atoms. When a lysine molecule was used instead of the proline ligand, compounds 4–6 with different structures were obtained. In 4, the γ-octamolybdates are firstly linked to a 1D chain via sharing oxygen atoms, and then adjacent chains are joined together by trinuclear {Cu3(lys)2} coordination fragments to yield a 2D network as a rare (3,6)-connected net with the Schläfli symbol (3·62)(34·42·62·74·83). When Zn2+ and Co2+ cations were added to replace Cu2+, isostructural 5 and 6 were obtained, respectively, and they are constructed from lysine functionalized γ-octamolybdates [Mo8O26(lysH)2]2− and free metal–H2O coordination cations. The activities of 1–6 against two human tumor cell lines (human breast cancer MCF-7 and human liver hepatocellular cells HepG2) were investigated in vitro. Cu- and Zn-directed amino acid functionalized POMs exhibit higher activities than Co-directed POMs and the parent amino acid functionalized octamolybdates ([Mo8O26(pro)2]4− and [Mo8O26(lysH)2]2−), which opens up new ways of developing novel drugs based on amino acid functionalized molybdate clusters.

Six 3D architectures based on lanthanide-substituted polyoxometalosilicates, KLn[(H2O)6Ln]2[(H2O)4LnSiW11O39]2·nH2O (Ln = La 1, n = 42; Ce 2, n = 40), H[(H2O)6Nd]2[(H2O)7Nd][(H2O)4NdSiW11O39][(H2O)3NdSiW11O39]·13H2O (3), H2K2[(Hpic)(H2O)5Ln]2[(H2O)4LnSiW11O39]2·nH2O (Ln = La 4, n = 18.5; Ce 5, n = 35; Nd 6, n = 36; Hpic = 4-picolinic acid), have been synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 are isostructural, built up of lanthanide-substituted polyoxoanions [{(H2O)4Ln(SiW11O39)}2]10− linked by Ln3+ cations to form a 3D open framework with 1D channels. The polyoxoanion [{(H2O)4Ln(SiW11O39)}2]10− consists of two α1-type mono-Ln-substituted Keggin anions. When Nd3+ ion was used instead of La3+ or Ce3+ ions, compound 3 with a different structure was obtained, containing two kinds of polyoxoanions [{(H2O)4Nd(SiW11O39)}2]10− and [{(H2O)3Nd(SiW11O39)}2]10− which are connected together by Nd3+ ions to yield a 3D framework. When 4-picolinic acid was added to the reaction system of 1–3, isostructural compounds 4–6 were obtained, constructed from the polyoxoanions [{(H2O)4Ln(SiW11O39)}2]10− linked by picolinate-chelated lanthanide centers to form a 3D channel framework. From a topological viewpoint, the 3D nets of 1, 2, 4, 5 and 6 exhibit a (3,6)-connected rutile topology, whereas the 3D structure of 3 possesses a rare (3,3,6,10)-connected topology. The magnetic properties of 2, 3, 5 and 6 have been studied by measuring their magnetic susceptibilities in the temperature range 2–300 K.

A new Anderson-anion-templated inorganic–organic hybrid compound, H[(bitdc)Ni(H2O)3]2[IMo6O24]·6H2O (1) (bitdc = N,N′-bis(isonicotinoyl)-trans-1,2-diaminocyclohexane), has been synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, Powder XRD and single‐crystal X-ray diffraction. Compound 1 is made up of Anderson-type polyoxoanions [IMo6O24]5− and dinuclear [(bitdc)2Ni2(H2O)6]4+ coordination complexes to yield an intriguing 3D supramolecular host–guest structure. To our best knowledge, compound 1 represents the first example of host–guest compounds with Anderson anions as template. The photocatalytic properties and magnetic properties of 1 have been investigated.By introducing the flexible N,N′-bis(isonicotinoyl)-trans-1,2-diaminocyclohexane ligand, a new host–guest hybrid compound constructed from Anderson-type polyoxoanion templates and dinuclear metal–organic coordination complexes, is reported, which exhibits good activity in photocatalyzing degradation of organic dye RhB.Highlights► Anderson-type polyoxoanion was utilized as template to construct a 3D supramolecular host–guest compound for the first time by low temperature co-solvothermal strategy. ► Anderson-anion-templated host–guest compound 1 shows good catalytic activity in photocatalyzing degradation of organic dye RhB, which may facilitate the design of new polyoxometalate-based host–guest materials with interesting photocatalytic properties. ► The flexible N,N′-bis(isonicotinoyl)-trans-1,2-diaminocyclohexane ligand was synthesized and first introduced to the polyoxometalate systems to construct hybrid frames.

By introducing the flexible ligands 3- or 4-pyridylacrylic acid into the Anderson-type polyoxometalate system, three new hybrid frameworks were obtained: [(3-Hpya)2Na][(3-Hpya)2Mn(H2O)2][CrMo6H6O24]·4H2O 1 (3-Hpya = 3-(3-pyridyl)acrylic acid), α-(4-Hpya)2{[(4-Hpya)2(H2O)3Mn]2[(H2O)4Mn(CrMo6H6O24)2]}·12H2O 2-α, β-(4-Hpya)2[(4-Hpya)2(H2O)4Mn][CrMo6H6O24]{[(4-Hpya)(H2O)3Mn]2(CrMo6H6O24)}·12H2O 2-β, (4-Hpya = 3-(4-pyridyl)acrylic acid). All compounds have been characterized by elemental analysis, IR and UV-vis spectroscopy, TG analysis, and single crystal X-ray diffraction. Compound 1 is made up of [CrMo6H6O24]3− polyoxoanions covalently linked by Mn–3-Hpya and Na–3-Hpya complexes to yield an unprecedented 2D network, which represents the first example of 2D hybrid assemblies based on Anderson-type polyoxometalates and manganese complexes, displaying the common 2D (4,4) topological net. When the 4-Hpya ligand was used, two polymorphic compounds 2-α and 2-β were obtained. Polymorphism in 2-α and 2-β arises from the different connectivity between polyoxoanions and manganese units. Compound 2-α is a bi-supporting structure composed of a dimeric cluster containing two Anderson polyoxoanions connected by a bridging manganese group, and two Mn–4-Hpya complexes. Compound 2-β is built up of bi-supporting polyoxometalate clusters, isolated Anderson polyoxoanions and Mn–4-Hpya fragments to yield a 3D supramolecular channel framework. Magnetic susceptibility studies performed on 1 and 2 reveal weak antiferromagnetic coupling between the metal centers in each case.

The solvothermal reaction of In(III) and 1,2,4,5-benzeneteracarboxylic acid with the presence of piperazine leads to the generation of a novel 3D chiral porous coordination polymer with PtS topological net. Interestingly, the resulting crystals were not a racemic mixture but enantiomeric excess, which was confirmed by the measurement of optical rotation of bulk samples using solid vibrational circular dichroism (VCD) spectra and the solid circular dichroism (CD) spectra based on large crystals from one crystallization. High-pressure CO2 and CH4 adsorption measurement at 298 K reveals that activated 1 can absorb 45.8 cm3 (STP)/g CO2 at 22 atm and 22.5 cm3 (STP)/g CH4 at 25 atm.

A family of three-dimensional (3D) architectures based on lanthanide-substituted polyoxometaloborate building blocks, [LnK(H2O)12][Ln(H2O)6]2[(H2O)4LnBW11O39H]2·20H2O (Ln = Ce 1, Nd 2), H2K2(H2O)n[(C6NO2H5)Ln(H2O)5]2[(H2O)4LnBW11O39H]2·18H2O (Ln = Ce n = 8 3, Nd n = 9 4, C6NO2H5 = pyridine-4-carboxylic acid), have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric (TG) analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 are isostructural, and are built up of lanthanide-substituted double-Keggin-type polyoxoanions [{(H2O)4Ln(BW11O39H)}2]10− linked by Ln3+ cations to form a 3D open framework with one-dimensional (1D) channels. The polyoxoanion [{(H2O)4Ln(BW11O39H)}2]10− consists of two α1-type mono-Ln-substituted Keggin anions, constituted by two [BW11O39H]8− polyoxoanions and two lanthanide cations. When pyridine-4-carboxylic acid ligand was added to the reaction system of 1, 2, compounds 3, 4 were obtained. Isostructural compounds 3 and 4 are constructed from the lanthanide-substituted double-Keggin-type polyoxoanions [{(H2O)4Ln(BW11O39H)}2]10− linked by the [Ln(C6NO2H5)]3+ bridges to form a 3D channel framework. From the topological point of view, the 3D nets of compounds 1−4 are binodal with three- and six-connected nodes and exhibit a rutile topology. Compounds 1−4 represent the examples of 3D architectures based on lanthanide-substituted polyoxometalates. The magnetic properties of compounds 1−4 have been studied by measuring their magnetic susceptibility in the temperature range 2−300 K.

A new double-Keggin-anion-templated host–guest hybrid compound, (H4pzdc)5[(H2pzdc)6(pzdc)2(H2O)2Na6][PW12O40]4·31H2O (1) (H2pzdc = 2,3-pyrazinedicarboxylic acid), has been synthesized and characterized by elemental analysis, IR spectroscopy, TG analysis, and single crystal X-ray diffraction. Compound 1 exhibits an intriguing double-Keggin-anion-templated 2D structure, made up of [PW12O40]3− Keggin-type polyoxoanions covalently linked with hexanuclear [Na6(H2pzdc)6(pzdc)2]2+ macrocations. To our best knowledge, it represents the first example of host–guest compounds with double-Keggin anions as coordinating template. Furthermore, compound 1 displays stronger photoluminescence properties than the H2pzdc ligand, due to the introduction of alkali metal cations.A new hybrid compound, originated from Keggin-type polyoxoanions and hexanuclear metal–organic coordination complex macrocations, are reported, which represent the first example of host–guest compounds with double-Keggin anions as coordinating template.

The hydrothermal reaction of Co(II)/Cu(II), 5-hydroxyisophthalic acid and dipyridophenazine leads to the generation of two 3D chiral coordination polymers, [M(hip)(DPPZ)]n (M = Co(1), Cu(2), H2hip = 5-hydroxyisophthalic acid, DPPZ = dipyridophenazine), which contain M-hip-M helical chains (M = Co, Cu) and possess a new four-connected 66 topological net. The resulting crystals were not a racemic mixture but an enantiomeric excess, which was confirmed by the measurement of optical rotation of the bulk samples using solid state vibrational circular dichroism (VCD) and solid circular dichroism (CD) based on the large crystals from one crystallization. The magnetic properties of 1 and 2 have been investigated by variable-temperature magnetic susceptibility and magnetization measurements, and the results reveal that antiferromagnetic interactions exist in 1 and 2.

Two new hybrid compounds with cadmium cations/coordination complexes as linkers, (C6H5NO2)4[(H2O)14Cd3(CrMo6H6O24)2] 1 (C6H5NO2 = pyridine-4-carboxylic acid) and H[(H2O)2(C6H5NO2)(C6H4NO2)Cd]2[CrMo6H6O24]·9H2O 2 (C6H5NO2, C6H4NO2 = pyridine-3-carboxylic acid), have been synthesized and characterized by elemental analyses, IR, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the polar space group Pc and is made up of [CrMo6H6O24]3− polyoxoanions covalently linked by cadmium cations to yield an unprecedented one-dimensional chain, which represents the first example of one-dimensional assemblies based on Anderson-type POMs and cadmium cations. Adjacent inorganic chains are further in close contact by pyridine-4-carboxylic acid glues to form three-dimensional supramolecular polar networks via strong hydrogen-bonding interactions. Compound 2 exhibits a three-dimensional supramolecular channel framework constructed from cationic cadmium-pyridine-3-carboxylic acid coordination polymer sheets pillared by Anderson-type polyoxoanions, with dissociated water molecules situated in the channels. Furthermore, both of the compounds exhibit photoluminescent properties at ambient temperature.

A pair of enantiomerically pure polyoxometalates, (C4NH7O4)[Na2(l-C4H8N2O3)2(H2O)9Zn]2[CrMo6H6O24]2 · 7H2O (l-1), and (C4NH7O4)[Na2(d-C4H8N2O3)2(H2O)9Zn]2[CrMo6H6O24]2 · 7H2O (d-1), have been synthesized for the first time and characterized by elemental analyses, IR, TG, UV and single crystal X-ray diffraction. l-1 and d-1 are enantiomers and crystallize in the chiral space group P21212. To our best knowledge, they represent the first examples of 1D homochiral polyoxometalate compounds constructed from Anderson-type polyoxoanions.A pair of enantiomer, originated from achiral Anderson-type polyoxometalate building units and chiral metal–organic coordination complex fragments, are reported, which represent the first examples of 1D homochiral polyoxometalate compounds featuring single helix.

Six 3D architectures based on lanthanide-substituted polyoxometalosilicates, KLn[(H2O)6Ln]2[(H2O)4LnSiW11O39]2·nH2O (Ln = La 1, n = 42; Ce 2, n = 40), H[(H2O)6Nd]2[(H2O)7Nd][(H2O)4NdSiW11O39][(H2O)3NdSiW11O39]·13H2O (3), H2K2[(Hpic)(H2O)5Ln]2[(H2O)4LnSiW11O39]2·nH2O (Ln = La 4, n = 18.5; Ce 5, n = 35; Nd 6, n = 36; Hpic = 4-picolinic acid), have been synthesized and characterized by elemental analysis, IR and UV-vis spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 are isostructural, built up of lanthanide-substituted polyoxoanions [{(H2O)4Ln(SiW11O39)}2]10− linked by Ln3+ cations to form a 3D open framework with 1D channels. The polyoxoanion [{(H2O)4Ln(SiW11O39)}2]10− consists of two α1-type mono-Ln-substituted Keggin anions. When Nd3+ ion was used instead of La3+ or Ce3+ ions, compound 3 with a different structure was obtained, containing two kinds of polyoxoanions [{(H2O)4Nd(SiW11O39)}2]10− and [{(H2O)3Nd(SiW11O39)}2]10− which are connected together by Nd3+ ions to yield a 3D framework. When 4-picolinic acid was added to the reaction system of 1–3, isostructural compounds 4–6 were obtained, constructed from the polyoxoanions [{(H2O)4Ln(SiW11O39)}2]10− linked by picolinate-chelated lanthanide centers to form a 3D channel framework. From a topological viewpoint, the 3D nets of 1, 2, 4, 5 and 6 exhibit a (3,6)-connected rutile topology, whereas the 3D structure of 3 possesses a rare (3,3,6,10)-connected topology. The magnetic properties of 2, 3, 5 and 6 have been studied by measuring their magnetic susceptibilities in the temperature range 2–300 K.

Four new architectures containing [Co2Mo10H4O38]6− polyoxoanions, (C2N2H10)2[Sr(H2O)5][Co2Mo10H4O38]·2H2O 1, (C2N2H10)2[Ba(H2O)3][Co2Mo10H4O38]·3H2O 2, (C3N2H12)2[Sr(H2O)5][Co2Mo10H4O38]·3H2O 3 and (C3N2H12)[Ba(H2O)4][Ba(H2O)4][Co2Mo10H4O38]·2H2O 4 (C2N2H10 = ethylenediamine; C3N2H12 = 1,3-propanediamine) have been synthesized and characterized by elemental analysis, IR spectroscopy, solid diffuse reflective spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compounds 1 and 2 obtained in the presence of ethylenediamine, are made of Evans–Showell-type anions [Co2Mo10H4O38]6−, linked by Sr2+ or Ba2+ cations to form 3D frameworks. To our knowledge, compound 1(2) represents the first example of 3D architecture in which the Evans–Showell anions [Co2Mo10H4O38]6− were linked by pure alkaline earth cations. When propanediamine was used instead of ethylenediamine, compounds 3 and 4 with 2D networks were obtained. This phenomenon indicates that the organic cations, which adjust the reaction pH values, can induce different dimensional inorganic frameworks. As heterogeneous catalysts, compounds 1–4 show excellent catalytic performance in the cyanosilylation of carbonyl compounds. Furthermore, these catalytic reactions were performed under solvent-free conditions using only a low amount of the catalysts, and these catalysts can be recovered and reused without displaying any significant loss of activity. As far as we know, compounds 1–4 represent the first examples of cyanosilylation catalyzed by POM-based species containing alkaline earth metal cations.

The hydrothermal reaction of Co(II)/Cu(II), 5-hydroxyisophthalic acid and dipyridophenazine leads to the generation of two 3D chiral coordination polymers, [M(hip)(DPPZ)]n (M = Co(1), Cu(2), H2hip = 5-hydroxyisophthalic acid, DPPZ = dipyridophenazine), which contain M-hip-M helical chains (M = Co, Cu) and possess a new four-connected 66 topological net. The resulting crystals were not a racemic mixture but an enantiomeric excess, which was confirmed by the measurement of optical rotation of the bulk samples using solid state vibrational circular dichroism (VCD) and solid circular dichroism (CD) based on the large crystals from one crystallization. The magnetic properties of 1 and 2 have been investigated by variable-temperature magnetic susceptibility and magnetization measurements, and the results reveal that antiferromagnetic interactions exist in 1 and 2.

The solvothermal reaction of In(III) and 1,2,4,5-benzeneteracarboxylic acid with the presence of piperazine leads to the generation of a novel 3D chiral porous coordination polymer with PtS topological net. Interestingly, the resulting crystals were not a racemic mixture but enantiomeric excess, which was confirmed by the measurement of optical rotation of bulk samples using solid vibrational circular dichroism (VCD) spectra and the solid circular dichroism (CD) spectra based on large crystals from one crystallization. High-pressure CO2 and CH4 adsorption measurement at 298 K reveals that activated 1 can absorb 45.8 cm3 (STP)/g CO2 at 22 atm and 22.5 cm3 (STP)/g CH4 at 25 atm.

Three new architectures based on Anderson-type polyoxometalates, (3-H2pya)[(3-Hpya)2Ag][AgAlMo6H6O24]·3H2O 1, HNa2[(3-pya)(3-Hpya)Ag]2[AlMo6H6O24]·8H2O 2 and [(3-Hpya)2Ag][(H2O)2Ag]2[AlMo6H6O24]·2H2O 3 (3-Hpya = 3-(3-pyridyl)acrylic acid), have been synthesized at the different pH values and characterized by elemental analysis, IR spectroscopy, TG analysis, powder X-ray diffraction and single crystal X-ray diffraction. Compound 1 was obtained at lower pH value (2.50), and represents a 3D host–guest compound containing the Ag-3-Hpya coordination complex guest and the 3D [AgAlMo6H6O24]2− host. The host framework exhibits a 4-connected diamond topology, and is constructed from [AlMo6H6O24]3− clusters connected by Ag+ cations. When the pH value was increased slightly, compound 2 was obtained with a 1D chain structure built up of Anderson polyoxoanions, Ag-3-Hpya coordination complexes and binuclear sodium clusters. By further increasing the pH value (3.50), compound 3 was isolated as a 2D network in which [AlMo6H6O24]3− clusters are linked together by Ag+ cations and Ag-3-Hpya coordination complexes. Their structural differences reveal that the pH value of the reaction system is the key factor influencing the structure and topology of three compounds. The UV-visible-NIR diffuse reflectivity spectra of 1–3 show that they can be regarded as a wide gap semiconductor. Furthermore, the pyrolysis of 1–3 produces three nanocomposites 1′–3′ composed of silver microparticles dispersed in the metal oxides. The photocatalytic properties of 1′–3′ have been investigated.